Intramuscle fat infiltration in non-dialysis CKD: clinical determinants and association with mortality

ABSTRACT

BACKGROUND: Intramuscle fat infiltration (IFI) is an important feature of aging currently understood as a cause of muscle weakness in elderly. Compared to healthy controls, IFI has been reported elevated in chronic kidney disease (CKD) patients. Its determinants and consequences, however, are unknown. METHODS: Cross-sectional study with mortality follow-up of 195 nephrology-referred patients with non-dialysis CKD stages 3-5. Mean age was 60±11 years, 61% were men and glomerular filtration rate (creatinine clearance) was 25±12 ml/min/1.73 m2 . We used computed tomography (CT) scan (Slice-O-Matic software version 5.0) of the third lumbar vertebra to quantify the degree of IFI (reported as % of fat within muscle area). Muscles evaluated by CT were psoas, transversus abdominis, rectus abdominis, external and internal obliques, erector spinae and quadratus lumborum. Coronary artery calcification score (CAC) was evaluated by CT, muscle strength by dynamometry (handgrip strength, HGS) and shown as standard values to normative tables. RESULTS: IFI was higher in women than in men (9.7±6 vs 6.3±4%, P 0.05), and was positively correlated (Spearman test) with age (rho =0.37), Charlson comorbidity score (rho=0.19), CAC (r=0.16) and CT-derived visceral (rho=0.37) and subcutaneous fat (rho =0.57). IFI was negatively associated with HGS (rho=-0.25) and CT-derived skeletal muscle mass (rho=-0.37)...(AU)